Coated lift-tab for resealing pop-top containers

ABSTRACT

A resealable pop-top beverage container is disclosed and claimed wherein a lift-tab is attached to the upper surface of the top of the container in a conventional manner such that when a finger-end of the lift-tab is raised, a swivel-end of the lift-tab forces a sealing plate to shear its connection to the edge of an access hole, thereby opening the access hole. The lift-tab of the invention includes a coating of a resilient material on at least its ventral side. When the lift-tab is rotated about a rotatable connector, the resilient material can juxtapose against the access hole thereby forming a reversible seal.

REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional patent application 60/952,168 filed by Hall and Taylor on Jul. 26, 2007, incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to resealable containers, particularly re-closable seals for pop-top aluminum cans.

2. Description of the Prior Art

The term “lift-tab” is used herein to refer to that family of finger-operated lever components used to prize open an access hole in pop-top-type containers and that remain attached to the container after the container is opened. “Lift-tab” includes, by way of example, finger-tabs, pop-top tabs, pull-tabs, and the like, as are well known opening devices used for soda cans, beer cans, juice cans, and the like. Such lift-tab based pop-top cans have been a commercial success for a number of years. Their primary advantage is that they obviate the need for a separate can opener, or “church key,” in order to open a beverage can and they reduce unsightly pop-top litter because the lift-tab is permanently connected to the container.

FIG. 1 shows a typical prior art lift-tab as used in a pop-top beverage container, namely a can 101 having a generally planar top 201 that has an upper surface surrounded by and contiguous with a rim 401. An access hole, generally oval, in the top is defined by an edge. While the beverage container is closed, the access hole is occluded by a sealing plate 301 that is connected to the edge by an inscribed break-line 1001, thereby providing a frangible waterproof seal. A lift-tab 501 is connected to the top by means of a connector 901, normally a simple rivet. The lift-tab has a finger-end 701 and a swivel-end 801. Near the finger-end of the lift-tab is normally a finger aperture 601.

A ventral surface of the lift-tab is defined as the lower or bottom surface of the lift-tab when the lift-tab is pressed down against the top of the container as shown in FIG. 1. In other words, the ventral surface of the lift-tab is the surface facing the upper surface of the top of the container when the lift-tab is in the closed position prior to opening the container.

The swivel-end 801 of the lift-tab the lift-tab is rotatably connected to the top 201 by a connector 901, allowing the lift-tab to rotate 360 degrees about the rivet. In addition to a pivot point, the rivet-connection also provides a fulcrum whereby raising the finger-end 701 forces the swivel-end 801 to move downward against the sealing plate 301, prizing the sealing plate loose from the top.

But for a hinge just under the aforesaid fulcrum, the access hole is circumscribed by the inscribed break-line. Because the swivel-end 801 of the lift-tab extends beyond the fulcrum, when the finger-end 701 of the lift-tab is lifted, the swivel-end is forced downward against the sealing plate, which, in turn, is pushed downward by means of the upward finger pressure on the finger-end, augmented by the mechanical advantage gained by the fulcrum, thereby forcing break-line 1001 to shear, whereby the access hole opens as the sealing plate is pushed into the container. The lift-tab is then conveniently pressed back down flat against the top of the container, leaving the access hole open and unobstructed so that the contents of the container can be poured out or accessed either by drinking directly from the access hole or by inserting a drinking straw into the access hole.

Currently existing pop-top containers, such as described above, are not resealable. Once the sealing plate is pushed into the interior of the can the sealing plate cannot be accessed to be pulled back into it's original position. This detracts significantly from the usefulness of such cans.

U.S. Pat. No. 4,681,238 to Sanchez is an example of attempts to provide resealable pop-top devices. Sanchez provides two sealing plates, both of which are attached to the under-surface of the top, in the interior of the can. In the un-opened configuration, a first sealing plate is disposed against the access hole from underneath the top. The sealing plate has a pliable layer on its upper, or dorsal, surface that provides a watertight seal. When the can is opened, this first sealing plate is pushed downwards in the same manner described above. In order to reseal the can, the lift-tab is twisted and a second internal sealing plate is rotated into position under the access hole. This second sealing plate also has a resilient layer that seals the hole from below. This approach to providing a resealable beverage container has never attained widespread use. The device, particularly the rivet connection, is complex and difficult to produce and requires significant re-tooling by the manufacturer. Furthermore, it is difficult to position the internal second sealing plate accurately under the access hole in order to make a watertight seal.

What is needed is a resealable pop-top container that is simple and effective in its use, inexpensive to produce without the need of re-tooling or extensive design modifications of the existing art.

BRIEF SUMMARY OF THE INVENTION

The invention is a resealable beverage container comprising an improved pop-top opening device of the type that is operated by pulling a lift-tab attached by one end to a fulcrum, thereby forcing a sealing plate to shear and bend downwards from the top to expose an access hole in the top of the container, the access hole being defined by an edge. The improvement comprises modifying the lift-tab by depositing or annealing a pliable pull-tab coat to at least the ventral surface of the finger-end of the lift-tab such that the coated lift-tab can be used to repeatedly to reseal the access hole Resealing the container is accomplished by rotating or swivelling the lift-tab so that the pliable pull-tab coat is adjacent the open access hole and then pressing the pull-tab down against the top of the container, wherein the pliable material on the ventral side of the pull-tab engages the edges of the opening to form a watertight seal. In order to unseal the resealed container, the coated portion of the lift-tab is lifted away from the access hole and rotated or swivelled out of the way, preferably back to its original position opposite the access hole. The preferred material of the pliable seal is medical-grade vinyl. The coated pull-tab optionally includes a straw-orifice with an orifice-closure comprising frangible break-lines that can be forced open to accommodate a drinking straw when the pull-tab is sealing the access hole.

The invention also comprises an improved lift-tab of the type used in pop-top beverage containers, the lift-tab having a finger-end, a swivel-end, and a ventral surface in which a pull-tab coat of resilient material is deposited on or annealed to the ventral surface of the finger-end.

The invention also comprises a resealable beverage container comprising: a top having an upper surface; an access hole in the top for accessing the contents of the container, the access hole defined by an edge; a rotatable swivel connector; a sealing plate connected to a substantial portion of the edge by a frangible break-line when the container is closed; and a pull-tab attached to the upper surface of the top by means of the swivel connector. The pull-tab comprises a ventral surface; a finger-end; a swivel-end opposite the finger-end, and a pull-tab coat comprising a resilient material deposited on or annealed to the ventral surface of the finger-end of the pull-tab. The rotatable connector connects the swivel-end of the pull tab to the upper surface of the top such that the pull-tab coat on the ventral surface of the finger-end of the pull-tab can be aligned over the access hole by rotating the pull-tab about the connector.

The invention also comprises a method of producing a resealable pop-top beverage container comprising the steps of depositing on or annealing a resilient pull-tab coat to the ventral surface of a pull-tab; attaching the pull-tab to the upper surface of the top by means of a rotatable connection between the pull-tab swivel-end and the top wherein the rotatable connection acts as a fulcrum whereby by raising the finger-end of the pull tab shears the connection between the sealing plate and the edge of the access hole and the sealing plate is forced into the lumen of the container, and wherein the pull-tab is rotatable about the rotation connection and configured such that the pull-tab coat on the ventral side of the pull-tab can be juxtaposed against the access hole for sealing the hole.

The method of producing the coated lift-tabs comprises the steps of treating vinyl or other material used to produce the seal with a standard aluminum to vinyl adhesive promoter, placing a lift-tab in a mold, injecting the vinyl or other material into the mold, placing the mold in an oven, baking the vinyl sufficiently long and at a sufficient temperature to cause the vinyl or other suitable material to become a resilient, solid state rubber, and removing the coated lift-tab from the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings identical reference numbers are employed to identify identical elements. The sizes and relative positions of the elements in the drawings are not necessarily to scale. For example, thicknesses are generally not drawn to scale and are enlarged to insure comprehension of the drawings.

FIG. 1 is a perspective view of a prior art pop-top container prior to being opened, as discussed above.

FIG. 2 is a perspective view of a pop-top container in a closed configuration with its lift-tab modified according to the invention.

FIG. 3 is a perspective view of a pop-top container in a resealed configuration with its modified lift-tab serving to reseal the access hole.

FIG. 4 is a top view of a lift-tab modified according to the invention.

FIG. 5 is a cross-sectional drawing through a lift-tab coated according to the invention and in a configuration for resealing a can.

FIG. 6 is a flow chart of the process of coating and attaching a lift-tab according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The inventive concepts, utility, and novel features of the invention are described here with reference to specific embodiments. These embodiments represent the best mode known to us for practicing and making the invention. Although the steps, elements, and limitations of the invention, as well as their structural and functional relationships, may be easily comprehended with respect to the preferred embodiments as disclosed herein, it is to be noted that these disclosures are representative of many possible embodiments that incorporate the inventive concepts of our invention.

Structural Features

The improved pop-top beverage container of the present invention provides a lift-tab that is modified to function as both a lift-tab and a resealing device. FIG. 2 shows the pop-top container 101 of FIG. 1, including access hole 301, rim 401, lift-tab 501, and rivet connector 901. The lift-tab shown in FIG. 2 has been modified according to the invention by depositing on or annealing to the pull-tab a pull-tab coat 102 made of resilient material. The lift-tab need not be otherwise modified, thereby minimizing additional production costs. The pull-tab is mounted on the upper surface of top 201, as described above with respect to the prior art, such that the ventral surface of the finger-end of the pull tab faces the upper surface of the top, and when the pull-tab is rotated about the connector 901 the ventral surface of the finger-end faces the access hole. Although our invention achieves its objective of resealing the container as long as the ventral portion of the finger-end of the pull-tab is coated, in our preferred embodiment the coating covers the entire pull-tab. It will be obvious from this disclosure that as long as the ventral surface of the part of the pull-tab that is juxtaposed against the access hole is coated, the access hole can be resealed. It is not necessary to coat the entire tab.

The pull-tab coat is made of a resilient material capable of conforming to the edge of the access hole, forming a frictional, watertight seal when the lift-tab is pressed against the hole. A vinyl material is preferred, and, more specifically, commonly known and easily obtainable medical-grade vinyl. This lift-tab coat thereby seals the access hole when the lift-tab is rotated 180 degrees about the rivet connector and pressed down onto the hole, as shown in FIG. 3.

FIG. 3 shows the pop-top container 101 of FIG. 2 with lift-tab 501 rotated 180 degrees about the rivet connection 901 and pressed down onto the access hole. Because the pull-tab coat 102 is resilient, it makes a water-tight frictional seal when the lift-tab is pressed against the access hole. However, it can be lifted free from the access hole by slight to moderate upward pressure on the finger-end 701 of the lift-tab. The lift-tab can then be rotated 180 degrees about the rivet connector and back into its original position so that the contents of the container can be easily accessed. This process of resealing and reopening the container can be repeated as many times as desired.

FIG. 4 shows a lift-tab 304 that has been modified according to the invention by the application of pull-tab coat 104. The geometrical shape of the lift-tab is characteristically triangular with rounded corners, but the invention is not limited to any particular shape of lift-tab. As indicated in FIG. 4) the coat may extend beyond the edges of the lift-tab. The extent by which the coat extends beyond the lift-tab will depend on the geometry and size of the lift-tab vis-a-vis the geometry and size of the access hole.

Lift-tabs also characteristically include a finger aperture 504 to make it easier for a user's finger-tip to engage the tab. The invention exploits such finger apertures by providing an straw orifice 604 through the pull-tab coat for inserting a drinking straw through the coating, through the finger aperture, and into the lumen of the container. The straw orifice 604 is preferably fashioned in the pull-tab coat by inscribing frangible break-lines 704 converging in a circular pattern. Thus, the straw orifice is watertight until a straw is forced through it.

There is also provided in the lift-tab, as is common in the existing art, a rivet aperture 204 for receiving the rivet that rotatably connects the lift-tab to the top. Except for applying the pull-tab coat, the means of producing the pop-top beverage container need not be modified at all, thereby avoiding expensive re-tooling costs that are required by other approaches.

FIG. 5 shows the modified lift-tab in cross-section as it appears when it is sealing the access hole. The figure shows a relevant portion of the top 105 of container 505. The top extends over the edge of the container to form the rim 705. Lift-tab 205 is coated with the pull-tab coat 305 and pressed against the top 105 in order to seal the access hole from leakage of the contents from the lumen 605 of the container. The modified lift-tab is pivotally connected to the top by means of rivet connection 405. Because the pull-tab coat is resilient, it protrudes into the lumen of the container as indicated by the bulge 305 a to provide a watertight seal.

Manner of Using

By providing the foregoing coated pull-tab, one is able to easily produce a resealable pop-top beverage container. Having produced such a container with a coated pull-tab, the manner of using our invention is simple, straight-forward, and almost intuitive for anyone who has opened a conventional pop-top can. The initial step of opening the container is no different than that of opening a standard pop-top container. The finger-end 701 of the lift-tab 501 is prized upwards, forcing the swivel-end 801 downward against the sealing plate 301 and breaking the frangible watertight seal between the sealing plate and the edge of the access hole, thus opening the access hole. The sealing plate is thusly bent downwards and into the interior of the container. As is commonly done in the existing art, the lift-tab can then be pressed back down against the top to get it out of the way while the beverage is being accessed.

When the user desires to reseal the container, the lift-tab is rotated about the rotatable connector 901, until the ventral surface of the finger-end is juxtaposed against the access hole. In the preferred embodiment, the lift tab must be rotated approximately 180 degrees about the rivet connector in order to align the lift tab with the access hole for sealing. When the lift-tab is positioned over the access hole, the lift-tab is pressed down and the resilient coating seals the access hole by frictional forces between the pull-tab coat and the edge of the hole.

When the user wishes to re-open the container, she lifts up on the leading edge of the lift-tab, pulling the pull-tab coat free of the edge. She then rotates the tab enough to reveal the open access hole.

Once the lift-tab is pressed down on the access hole to reseal the container, if the embodiment of the invention being used includes an optional straw orifice 604 as shown in FIG. 4, a straw can be forced through the orifice by breaking the frangible break-lines 704.

The rotations of the lift-tab of 180 degrees disclosed above are preferred; however, a rotation of any angle that accommodates the needs of the user and the geometry of the lift-tab and access hole are sufficient and anticipated by this disclosure.

Manner of Making

One of the advantages of our invention over the existing art is that our invention is produced easily and economically. The coating can be applied to any lift-tab without the need to re-tool the entire can-producing process. A preferred process for applying the coating to the lift-tab is as follows.

Depending on the materials employed to produce the lift-tab, the lift-tab is optionally coated with a vinyl adhesion promoter specific for that material 106. The lift-tab is placed in a two-part mold 206, which is closed and sealed. Liquid vinyl is injected 306 and a mold-heater is positioned adjacent the mold 406, or the mold is placed in an oven. The mold is heated 506 for a sufficient length of time and to a sufficient temperature to allow the liquid vinyl to solidify to a rubberized state having enough resiliency to properly seal the access hole when pressed into position. These parameters, of course, depend upon the materials being employed. With respect to a medical grade vinyl applied to aluminum pull-tabs, we have found that approximately 350° C. for 30 seconds is effective. After baking, the mold-heater is removed 606 and the mold is refrigerated 706. The mold is then broken 806 to extract the coated lift-tab, which is then attached to the can 906 using existing and well-known techniques.

On the basis of the present disclosure, those skilled in the art will be able to determine, without undue experimentation, the optimum type of vinyl or other resilient substance to employ and the optimum conditions for coating the lift-tabs with the vinyl or other resilient substance, depending on various considerations such as the material the tab is made of, expected ambient temperatures in which the invention will be used, and the like. While the foregoing process produces good results, those skilled in the art will realize from this disclosure that other processes for coating a lift-tab with resilient coating are obvious alternatives.

SUMMARY

From the foregoing description, the novelty, utility, and means of making and using our invention will be readily apprehended. It is to be understood that our invention is not limited to the embodiments disclosed above but encompasses any and all embodiments lying within the scope of the disclosure and claims. 

1. An improved lift-tab of the type used in a pop-top beverage container, the lift-tab being attached to the upper surface of a top of the container, and the lift-tab having a finger-end, a swivel-end, and a ventral surface, the improvement comprising a pull-tab coat of resilient material deposited on or annealed to at least the ventral surface of the lift-tab, whereby said pull-tab coat can be used to reseal the container by juxtaposing the coated ventral surface against an access hole in the top of the container.
 2. The improved lift-tab of claim 1 wherein the improvement further comprises a straw-orifice provided in said pull-tab coat, wherein said straw-orifice comprises frangible break-lines inscribed in said pull-tab coat.
 3. A resealable beverage container comprising: a. a top having an upper surface, b. an access hole in said top for accessing the contents of said resealable beverage container, said access hole defined by an edge; c. a swivel connector; d. a sealing plate connected to a substantial portion of said edge by a frangible break-line when the container is closed; e. a pull-tab, said pull-tab comprising a i) ventral surface, ii) a finger-end, and iii) a swivel-end opposite said finger-end; and, f. a pull-tab coat comprising a resilient material deposited on or annealed to said ventral surface of said pull-tab, wherein said pull-tab coat is configured to seal said access hole when said pull-tab is juxtaposed against said access hole, wherein said swivel connector connects said swivel-end of said pull tab to said upper surface of said top such that said pull-tab can be juxtaposed against said access hole for resealing said container.
 4. A method of producing a resealable pop-top beverage container wherein said beverage container comprises i) a top, ii) an access hole in the top, wherein the access hole is defined by an edge, iii) a sealing plate, wherein said sealing plate is connected to the edge of the access hole by means of a frangible, waterproof seal when the container is closed, and, iv) a pull-tab comprising a finger-end, a swivel-end, and a ventral surface, said method comprising the steps of: (a) depositing on or annealing to the ventral surface of the pull-tab a pull-tab coat made of resilient material; and, (b) attaching the pull-tab to the upper surface of the top by means of a rotatable connection between the pull-tab swivel-end and the top wherein the rotatable connection acts as a fulcrum, whereby raising the finger-end of the pull tab shears the connection between the sealing plate and the edge of the access hole and the access hole is opened as the sealing plate is forced into the lumen of the container, and wherein the pull-tab is rotatable about the rotation connection whereby the pull-tab coat on the ventral side of the pull-tab can be juxtaposed against the access hole for sealing the container.
 5. The method of claim 4 wherein the pull-tab coat is a resilient material.
 6. The method of claim 4 wherein the pull tab coat is vinyl.
 7. The method of claim 4 wherein the pull tab coat is a medical grade vinyl. 